In Silico Identification of Potential Plastic-Active Proteins in Fungi Through a Proteome Comparison Using the Pazy Database

The widespread use of plastics has created a global pollution problem, posing significant environmental challenges due to their resistance to degradation. Polyethylene (PE) is the most prevalent polymer, other widespread plastics are polyethylene terephthalate (PET), polyamide (PA), and polyurethane (PUR). Fungi are known to degrade various synthetic compounds including plastics, yet while bacterial plastic-degrading enzymes are well-documented, fungal enzymes remain underexplored, particularly in species with limited genomic data. This study investigates the potential of fungal species to degrade plastic polymers, focusing on the identification of plastic-active enzymes using the Plastics-Active Enzymes Database (PAZy). We employed orthology analysis to identify potential plasticdegrading enzymes in fungal proteomes from Trichoderma reesei, Fusarium concentricum, Aspergillus hortae, Fusarium annulatum, and Cladosporium cladosporioides by comparing them to positive controls Penicillium citrinum and Aspergillus versicolor. These fungal species were selected for their taxonomic similarity to the environmental isolates from the collection of the Laboratorio de Bioinformática Aplicada (LABAP). The findings revealed a diverse set of fungal enzymes potentially involved in plastic degradation across 19 orthogroups, with conserved regions and motifs associated with carboxylesterases, hydrolases, and cutinases. Phylogenetic analysis indicated distinct evolutionary paths for fungal and bacterial plastic-degrading enzymes, with shared mechanisms evident in some clusters. Patent searches confirmed the novelty of the identified fungal enzymes, with minimal overlap in existing patents, particularly within Latin America. This study underscores the potential of fungi as a source of novel plastic-degrading enzymes and provides a foundation for future experimental validation and biotechnological exploitation, especially in regions with rich biodiversity like Costa Rica.